Dual-MAG heat source dual-filament submerged arc build-up welding method

Abstract

The invention discloses a dual-MAG heat source dual-filament submerged arc build-up welding method which aims to solve the problems such as gas holes in aluminum bronze MAG build-up welding, incomplete fusion, slag inclusion, welder poisoning caused by copper welding smoke gas, and the like. The dual-MAG heat source dual-filament submerged arc build-up welding method comprises the following steps:I, removing spray nozzles for dual welding guns connected to a dual-MAG power supply, adopting dual conductive nozzles to separately clamp dual welding wires, embedding protective soldering flux, andadopting direct-current reverse connection for the dual-MAG power supply; II, enabling the dual welding guns to simultaneously arc and feed wires, enabling end parts of dual wires to define an included angle to advance side by side, and enabling two electric arcs to define a congruent melting tank; III, regulating current of the dual-MAG power supply to be 160A-200A, enabling voltage to be 24V-28V, enabling welding speed to be 30 cm / min to 40cm / min, enabling offset of adjacent two welding beads to be 1 / 3-1 / 2 of width of an upper welding seam (7), performing build-up welding on 3-4 wear-resisting layers, and enabling the thickness of a bottoming layer to be not greater than 3 mm. The welding method disclosed by the invention can be applied to the field of aluminum bronze build-up welding engineering of a water turbine.

Description

technical field [0001] The invention relates to the field of submerged arc welding, in particular to a method for submerged arc surfacing welding with double MAG heat sources and double filaments. Background technique [0002] Ball valves and upstream and downstream flanges of large pumped-storage turbines, due to the repetitive reciprocating movement during the operation of the unit, need to surfacing wear-resistant aluminum bronze layer on the low alloy steel or carbon steel side of the friction contact surface, so as to improve the performance of the workpiece , improve the service life, save more expensive copper alloy materials and reduce costs. The remaining thickness of the aluminum bronze surfacing layer after processing is generally 6mm-8mm, and in order to ensure the alloy composition and performance of the cladding layer, the surfacing thickness is generally required to be more than 10mm. In production, MIG welding is often used for aluminum bronze surfacing weld...

AI Technical Summary

Problems solved by technology

In production, MIG welding is often used for aluminum bronze surfacing welding. On the one hand, due to the large differences in thermal conductivity, shrinkage rate, and melting point between aluminum bronze and steel, the weldability is poor, and the process parameters are difficult to control. Defects such as porosity, slag inclusion, and lack of fusion cause a large amount of repair costs to be wasted; on the other hand, a large amount of smoke generated by gas-shielded surfacing welding of aluminum bronze often leads to copper poisoning of welders; moreover, gas-shielded welding of aluminum bronze requires strict grinding and cleaning Spatter and scale, high labor intensity for welders

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